LDPC Transmitter Parity Scheduling for Coding and Diversity Gain
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Solution Overview
Problem
Current signal transmission methods for digital broadcasting lack efficient mechanisms to enhance performance and provide improved services, particularly in terms of coding gain and diversity gain, for high-definition digital television and portable broadcasting.
Innovation Solution
A transmitter system incorporating a Low Density Parity Check (LDPC) encoder, repeater, puncturer, and additional parity generator to encode, repeat, puncture, and generate additional parity bits for broadcasting signals, optimizing signal transmission by adjusting parity bits and repetition patterns.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If additional parity bits are generated and transmitted, then coding gain and diversity gain are improved, but transmission bandwidth and system complexity increase
Solution Approach 1:
The patent generates additional parity bits in advance (in previous frames) before they are needed for decoding current frame transmissions. This preliminary generation allows the receiver to have parity bits ready for combining, improving decoding reliability without requiring real-time computation during critical transmission periods.
Solution Approach 2:
The patent creates copies of parity bits by generating additional parity that replicates the function of original parity bits. These copied parity bits are then transmitted in different frames and combined at the receiver, providing redundancy and diversity gain without fundamentally changing the LDPC encoding structure.
2Reliability
If repetition of bits is performed in the LDPC codeword, then diversity gain is improved, but transmission time and processing overhead increase
Solution Approach 1:
The patent implements repetition by transmitting the same LDPC codeword bits at periodic intervals across multiple frames. This periodic transmission pattern ensures that if one transmission is lost or corrupted, the receiver can accumulate sufficient signal energy from repeated transmissions at different time instances, achieving diversity gain without continuous retransmission.
3Productivity
If puncturing of parity bits is performed, then transmission efficiency is improved, but decoding reliability deteriorates
Solution Approach 1:
The patent dynamically changes the puncturing pattern parameters based on channel conditions and transmission requirements. By adjusting which parity bits are punctured and generating corresponding additional parity bits, the system optimizes the balance between transmission efficiency (fewer bits transmitted) and decoding reliability (sufficient parity information available for error correction).
Data Source
AI summary
A transmitter is provided. The transmitter includes: a Low Density Parity Check (LDPC) encoder configured to encode input bits to generate an LDPC codeword including the input bits and parity bits to be transmitted to a receiver in a current frame; a repeater configured to repeat, in the LDPC codeword, at least some bits of the LDPC codeword in the LDPC codeword so that the repeated bits are to be transmitted in the current frame; a puncturer configured to puncture some of the parity bits; and an additional parity generator configured to select at least some bits of the LDPC codeword including the repeated bits, and generate additional parity bits to be transmitted in a previous frame of the current frame.